Dummy plugs used for the start-up of teeming in the continuous casting of various metal shapes are well known as is also the use of a removable connection head for such dummy plugs generally employing a packing strip or cord made of plastic covered with scrap for cooling, to seal the gap between the connection head and the walls of the mold. For example, Austrian Patent AT PS No. 352,924 describes a dummy bar head which uses a seal supported by a spring plate which is pushed into grooves in the upper surface of the head of the dummy bar. This seal automatically closes off the gap between the connection head and the mold walls, but is not particularly effective because it also can be burnt out by the molten metal at the start of casting with the result that metal can penetrate into the gap between the dummy bar and interfer with the withdrawal action. The risk of a freeze-up at the critical movement of the initiation of teeming can be minimized by the use of cooling scrap, but to do so is cumbersome. In addition, cleaning out the grooves in the connection end of the dummy bar is costly and time consuming.
Another known device described in European Patent No. 114,309 employs a removable connection head on the end of a dummy bar which can be attached to the dummy bar before insertion into the casting mold. The connection head is provided with a seal held by a seal holder which is covered and temporarily protected. At the start-up of teeming the seal is vaporized and dissolved by the molten metal as it enters the mold. This arrangement, however, also has the drawback of requiring the use of cooling scrap which introduces the risk of scratching the inner surfaces of the mold and of the supporting guides for the casting further downstream. Also the seal holder has to be replaced after each start-up.
In addition due to the narrow shape and thin cross-section of strip metal and the consequent poor accessability and constricted room, these known types of connection heads are not suitable for use in the continuous casting of strip metal, especially steel.
It is therefore an object of this invention to provide a connection head for use with a dummy strip in the initiation of teeming in the continuous casting of strip metal, which connectin head can be mounted on the end of the dummy strip outside of the mold in a quick, simple and exact manner to form an efficient and effective seal without requiring the use of cooling scrap.